I have menitoned in this blog before that I launched a FREE site dedicated to providing buyers with information to get the best deals in online auctions - http://www.AuctionCapture.com.

Over the past few months, more and more people have started using it and winning auctions. We've taken samples* and done analysis, and  we've seen some interesting trends:

• Auctions that end from 6-11pm EST on Sundays have the highest closing prices. This is the time window that seems produce the lowest percentage of auctions that end without any bids.
  
  
• Auctions that end from 3-8am EST on Tuesday, Wednesday, and Thursday have the lowest closing prices.
  
  
• Auctions posted in the wrong category generally close at 15-20% lower than similar items in more closely related categories.
   
• Auctions posted with misspellings of key words in the titles close at 25% lower than similar items with correct spellings.
  
  
• Auctions from sellers with low starting bids and very high feedback have higher ending prices than similar auctions from sellers with lower feedback/newer accounts. It would seem that when sellers get a good reputation, more people visit and bid on their auctions. 
  
  
• There is more buyer loyalty than we expected. We saw a trend of repeat bidders and winners on auctions from sellers that they had previously won an auction from.
  

Summary:

I'd suggest that you consider buying at off peak times, creating saved searches with misspellings, and consider buying from new sellers.

* The representative sample used was a subset of data collected from November 2006-January 2007 in the Sports Memorabilia, Collectibles, and Cards categories across the multiple auction sites available on AuctionCapture. Results may vary using a larger sample over a longer period of time.